Started work on attaching F-785B attach angle to the F-785A backrest braceThis is another confusing task. Before you can attach the F-785B attach angle to the bottom of the F-785A backrest brace, you have to drill the holes in the F-785B attach angle, using the floor channel cover plate as a drill guide. These holes have screws that go into them, attaching the angle piece to the channel cover and the floor ribs. The drawing shows where to draw a line on the F-785B attach angle so you can line it up with the floor channel cover screw holes.

Here are the new holes in the F-785B attach angleNow it's time to figure out how to attach the angle to the F-785A backrest brace.

Placing the F-785B attach angle on the F-785A backrest braceIf you look at the drawing, you will see that the F-785B attach angle is not placed flush with the bottom of the F-785A backrest brace. There is an 1/8" gap from the "Vertex" of the attach angle. If you are like me, you are wondering at this point "what the hell is a vertex?". Oh well, back to the Internet. Here's the definition: "The point of intersection of lines or the point opposite the base of a figure". Got it? Me neither. Basically it's the outside corner of the angle piece. So I drew a line on the angle piece as a go-by.

Getting ready to drill the holes in the F-785A backrest braceAfter establishing the 1/8 inch gap from the "vertex", I clamped everything down, making sure that the angle piece was centered on the backrest brace. Then I used my 12 inch #30 drill bit to drill the holes, using the angle piece as the guide.

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This website was built to document the construction of an RV-9A in
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